Jeffrey Phillips (Former Employee)
Science and Products
Filter Total Items: 80
Estimating locations and total magnetization vectors of compact magnetic sources from scalar, vector, or tensor magnetic measurements through combined Helbig and Euler analysis Estimating locations and total magnetization vectors of compact magnetic sources from scalar, vector, or tensor magnetic measurements through combined Helbig and Euler analysis
The Helbig method for estimating total magnetization directions of compact sources from magnetic vector components is extended so that tensor magnetic gradient components can be used instead. Depths of the compact sources can be estimated using the Euler equation, and their dipole moment magnitudes can be estimated using a least squares fit to the vector component or tensor gradient...
Authors
J. D. Phillips, M.N. Nabighian, D.V. Smith, Y. Li
Preliminary integrated geologic map databases for the United States: Digital data for the generalized bedrock geologic map, Yukon Flats region, east-central Alaska Preliminary integrated geologic map databases for the United States: Digital data for the generalized bedrock geologic map, Yukon Flats region, east-central Alaska
The growth in the use of Geographic Information Systems (GIS) has highlighted the need for digital geologic maps that have been attributed with information about age and lithology. Such maps can be conveniently used to generate derivative maps for manifold special purposes such as mineral-resource assessment, metallogenic studies, tectonic studies, and environmental research. This report...
Authors
Alison B. Till, Julie A. Dumoulin, Jeffrey D. Phillips, Richard G. Stanley, Jessie Crews
Crustal insights from gravity and aeromagnetic analysis: Central North Slope, Alaska Crustal insights from gravity and aeromagnetic analysis: Central North Slope, Alaska
Aeromagnetic and gravity data are processed and interpreted to reveal deep and shallow information about the crustal structure of the central North Slope, Alaska. Regional aeromagnetic anomalies primarily reflect deep crustal features. Regional gravity anomalies are more complex and require detailed analysis. We constrain our geophysical models with seismic data and interpretations along...
Authors
R. W. Saltus, C. J. Potter, J. D. Phillips
Historical development of the gravity method in exploration Historical development of the gravity method in exploration
The gravity method was the first geophysical technique to be used in oil and gas exploration. Despite being eclipsed by seismology, it has continued to be an important and sometimes crucial constraint in a number of exploration areas. In oil exploration the gravity method is particularly applicable in salt provinces, overthrust and foothills belts, underexplored basins, and targets of...
Authors
M.N. Nabighian, M. E. Ander, V. J. S. Grauch, T.R. LaFehr, Y. Li, W. C. Pearson, J.W. Peirce, J. D. Phillips, M.E. Ruder
The historical development of the magnetic method in exploration The historical development of the magnetic method in exploration
The magnetic method, perhaps the oldest of geophysical exploration techniques, blossomed after the advent of airborne surveys in World War II. With improvements in instrumentation, navigation, and platform compensation, it is now possible to map the entire crustal section at a variety of scales, from strongly magnetic basement at regional scale to weakly magnetic sedimentary contacts at...
Authors
M.N. Nabighian, V. J. S. Grauch, R. O. Hansen, T.R. LaFehr, Y. Li, J.W. Peirce, J. D. Phillips, M.E. Ruder
Can we estimate total magnetization directions from aeromagnetic data using Helbig's integrals? Can we estimate total magnetization directions from aeromagnetic data using Helbig's integrals?
An algorithm that implements Helbig’s (1963) integrals for estimating the vector components (mx, my, mz) of the magnetic dipole moment from the first order moments of the vector magnetic field components (ΔX, ΔY, ΔZ) is tested on real and synthetic data. After a grid of total field aeromagnetic data is converted to vector component grids using Fourier filtering, Helbig’s infinite...
Authors
Jeffrey Phillips
Science and Products
Filter Total Items: 80
Estimating locations and total magnetization vectors of compact magnetic sources from scalar, vector, or tensor magnetic measurements through combined Helbig and Euler analysis Estimating locations and total magnetization vectors of compact magnetic sources from scalar, vector, or tensor magnetic measurements through combined Helbig and Euler analysis
The Helbig method for estimating total magnetization directions of compact sources from magnetic vector components is extended so that tensor magnetic gradient components can be used instead. Depths of the compact sources can be estimated using the Euler equation, and their dipole moment magnitudes can be estimated using a least squares fit to the vector component or tensor gradient...
Authors
J. D. Phillips, M.N. Nabighian, D.V. Smith, Y. Li
Preliminary integrated geologic map databases for the United States: Digital data for the generalized bedrock geologic map, Yukon Flats region, east-central Alaska Preliminary integrated geologic map databases for the United States: Digital data for the generalized bedrock geologic map, Yukon Flats region, east-central Alaska
The growth in the use of Geographic Information Systems (GIS) has highlighted the need for digital geologic maps that have been attributed with information about age and lithology. Such maps can be conveniently used to generate derivative maps for manifold special purposes such as mineral-resource assessment, metallogenic studies, tectonic studies, and environmental research. This report...
Authors
Alison B. Till, Julie A. Dumoulin, Jeffrey D. Phillips, Richard G. Stanley, Jessie Crews
Crustal insights from gravity and aeromagnetic analysis: Central North Slope, Alaska Crustal insights from gravity and aeromagnetic analysis: Central North Slope, Alaska
Aeromagnetic and gravity data are processed and interpreted to reveal deep and shallow information about the crustal structure of the central North Slope, Alaska. Regional aeromagnetic anomalies primarily reflect deep crustal features. Regional gravity anomalies are more complex and require detailed analysis. We constrain our geophysical models with seismic data and interpretations along...
Authors
R. W. Saltus, C. J. Potter, J. D. Phillips
Historical development of the gravity method in exploration Historical development of the gravity method in exploration
The gravity method was the first geophysical technique to be used in oil and gas exploration. Despite being eclipsed by seismology, it has continued to be an important and sometimes crucial constraint in a number of exploration areas. In oil exploration the gravity method is particularly applicable in salt provinces, overthrust and foothills belts, underexplored basins, and targets of...
Authors
M.N. Nabighian, M. E. Ander, V. J. S. Grauch, T.R. LaFehr, Y. Li, W. C. Pearson, J.W. Peirce, J. D. Phillips, M.E. Ruder
The historical development of the magnetic method in exploration The historical development of the magnetic method in exploration
The magnetic method, perhaps the oldest of geophysical exploration techniques, blossomed after the advent of airborne surveys in World War II. With improvements in instrumentation, navigation, and platform compensation, it is now possible to map the entire crustal section at a variety of scales, from strongly magnetic basement at regional scale to weakly magnetic sedimentary contacts at...
Authors
M.N. Nabighian, V. J. S. Grauch, R. O. Hansen, T.R. LaFehr, Y. Li, J.W. Peirce, J. D. Phillips, M.E. Ruder
Can we estimate total magnetization directions from aeromagnetic data using Helbig's integrals? Can we estimate total magnetization directions from aeromagnetic data using Helbig's integrals?
An algorithm that implements Helbig’s (1963) integrals for estimating the vector components (mx, my, mz) of the magnetic dipole moment from the first order moments of the vector magnetic field components (ΔX, ΔY, ΔZ) is tested on real and synthetic data. After a grid of total field aeromagnetic data is converted to vector component grids using Fourier filtering, Helbig’s infinite...
Authors
Jeffrey Phillips
*Disclaimer: Listing outside positions with professional scientific organizations on this Staff Profile are for informational purposes only and do not constitute an endorsement of those professional scientific organizations or their activities by the USGS, Department of the Interior, or U.S. Government